diff --git a/sql/item.cc b/sql/item.cc
index dcedfcb6d84..5c032e3356f 100644
--- a/sql/item.cc
+++ b/sql/item.cc
@@ -3907,7 +3907,9 @@ bool Item_field::fix_fields(THD *thd, Item **reference)
       {
         /* First usage of column */
         table->used_fields++;                     // Used to optimize loops
+        /* purecov: begin inspected */
         table->covering_keys.intersect(field->part_of_key);
+        /* purecov: end */
       }
     }
   }